Article,
Effects of Partial Isolation (Distance), Migration, and Different Fitness Requirements among Environmental Pockets upon Steady State Gene Frequencies
Biometrics, 22 (3): pp. 453-468 (1966)
Abstract
Expected gene frequencies are described for a simple genetic system. The development emphasizes the effects of different fitness requirements among environmental pockets, associated groups of individuals (colonies), and migration. The effects of isolation and migration are reflected as translations of the x1 and x2 displacement distances. The net effect of finite colony size is to reduce the magnitude of change in expected gene frequency per generation as compared to that obtained by infinite theory. For two special cases, a clinal variation in fitness and a pocket of differential fitness, a detailed analysis is given, including results of computer analyses. In general, a clinal variation in fitness yields a narrow hybrid belt. Peripheral areas of differential fitness for a genotype (the region being primarily neutral with respect to relative fitness of genotypes) or differences in fitness considerably less than those considered can lead to an extended belt. Migration can mask a pocket of differential fitness. Some critical pocket sizes corresponding to selected differential fitnesses are given. Interpretations for selected biological systems are made.
